Everyone doubts. Everyone trusts. Nobody trusts perfectly or doubts perfectly in everything and at all times and in all ways. So, you could always doubt more or get better at it. The question would be, then, should you?
To answer that we should probably discuss why you should do anything at all. Some say that everything that we should do is really only pragmatic--that it serves a practical purpose. Some say that what we should do are the higher things--striving for virtues. Others say that there is still another more external and unchanging standard--this is what you ought to do. So, if those are our options (if there is another then let me know) then which one would motivate us to doubt more and even better?
Pragmatism would only promote doubting and skepticism when it called for it. We would need to look at it on a case-by-case basis. So, three would not be a need to increase. Skepticism can only be seen as a virtue when it is freeing you from some untoward behavior or social ills. However, to be totally skeptical in all things can never be a virtuous goal mainly because it would keep you from all other virtuous goals which require trust. Even pragmatism requires a very great deal of trust. An objective ought would actually require that we only doubt when it is necessary in order to understand better what it is that we must do in light of this standard. We should doubt only to find out what it is that we should not doubt--the ultimate objective ought.
As we can see from a short assessment, there is never a reason to doubt perfectly all the time, in every way and in everything. Doubt is merely a tool to be used and never something to aspire to. It is not the ultimate goal of the pragmatist, the nobleman nor the believer in objective standards. So, being skeptical should not be anyone's goal. In fact, as French philosopher Blaise Pascal said,
"What then is man to do in this state of affairs? Is he to doubt everything, to doubt whether he is awake, whether he is being pinched or burned? Is he to doubt whether he is doubting, to doubt whether he exists?
No one can go that far, and I maintain that a perfectly genuine sceptic has never existed."
Pensees ( Blaise Pascal, Penguin Classics; Rev Ed edition, Translated by A. Krailsheimer)